Discovery launch set for April 5
Cape Canaveral - Nasa on Friday cleared space shuttle Discovery for launch on April 5 on one of its final cargo runs to the International Space Station before the fleet is retired later this year.
Liftoff of the spaceship and seven astronauts will be from the Kennedy Space Centre in Florida.
The shuttle will be carrying a cargo pod filled with science racks and equipment for the space station, which is nearing completion after more than a decade of construction 350 km above Earth.
Nasa has four flights remaining to finish outfitting the station, a $100bn project of 16 nations.
The US space agency has contracted with commercial launch service providers Space Exploration Technologies of California and Orbital Sciences Corp of Virginia to deliver cargo to the station as early as next year.
SpaceX, which was founded by billionaire Internet entrepreneur Elon Musk, plans to debut its Falcon 9 rocket with a demonstration mission next month from a newly refurbished launch pad at Cape Canaveral Air Force Station, just south of the shuttles' launch complex. Orbital's Taurus 2 launcher is expected to make its first flight next year.
Cargo vessels operated by Russia, Japan and Europe also will keep the station stocked with equipment, supplies and gear for six live-aboard crewmembers. All crew transport has been turned over to Russia in preparation for the shuttles' retirement later this year.
Nasa had been planning to develop a capsule-style spaceship to fly astronauts to the station, as well as the moon, but US President Barack Obama is calling for the program's cancellation. Instead, the White House wants to see if commercial firms can provide another option besides relying exclusively on the Russians, which charge $51m per seat for rides on their Soyuz capsules.
Obama is scheduled to host a space summit in Florida on April 15 in an attempt to win support for the new direction he envisions for Nasa. An independent panel of advisers, including aerospace executives, astronauts and renowned scientists, last year determined that the moon exploration initiative, known as Constellation, had been underfunded and had no hope of reaching its goal of returning astronauts to the moon by 2020.
The program's cancellation, however, has drawn sharp rebuke from some members of Congress, particularly from districts in Florida, Texas and Alabama that will bear the brunt of an estimated 9 000 engineering and technical job losses due to the shuttle program's end.
Discovery's mission, which is scheduled to last 13 days, is the 131st mission since shuttle flights began in 1981. The program has had two fatal accidents, which took the lives of 14 astronauts, and costs about $200m a month.
Obama proposes increasing Nasa's budget by about $2bn a year to jump-start commercial space taxi services, as well as invest in new technologies that would eventually lead to a human expedition to Mars.